Gene swapping is nothing new, being going on for millions of years. Nothing unnatural about that.


Fossil rhabdoviral sequences integrated into arthropod genomes

Here we searched for Rhabdoviridae (e.g. Rabies virus) sequences integrated into animal genomes. We identified 185 integrated rhabdoviral elements (IREs) coding for nucleoproteins, glycoproteins or RNA-dependent RNA polymerases; they were mostly found in the genomes of the mosquito Aedes aegypti and the blacklegged tick Ixodes scapularis.

Integrated rhabdoviral elements (IREs) were primarily generated through reverse transcription of viral mRNAs. This probably involved the machinery of transposable elements (TEs), since the number of IREs appears to correlate positively with the genomic TE content of their hosts; Indeed, nearly 50% of the A. aegypti genome consists of TEs.



Host-switching by a vertically transmitted rhabdovirus in Drosophila

Here, we describe four new sigma viruses, a group of vertically transmitted rhabdoviruses previously known in Drosophila. Using sequence data from these new viruses, and the previously described sigma viruses, we show that they have switched between hosts during their evolutionary history.

A sigma-like virus outside of the genus Drosophila suggests that these viruses may be widespread in Dipterans, if not insects as a whole. Unlike bacterial endosymbionts, the rapid evolution of the sigma virus genome makes it impossible to design a single pair of diagnostic PCR primers that can be used to test for new strains of the virus.



LINE-1 Elements in Structural Variation and Disease

In most cases, transposase binds at DNA transposon inverted repeat sequences, "cuts" the transposon from its existing location, and then "pastes" it into a new genomic location. DNA transposons have had an enduring effect on the human genome. For example, the recombination activating genes, RAG1 and RAG2, which are critical for V(D)J recombination and immune system development, likely were domesticated from the Tran-sib family of DNA transposons ~500 Mya. 

Engineered DNA transposons have practical applications, and can be exploited for useful purposes. For example, a reanimated salmon DNA transposon, Sleeping Beauty, has been used to discover genes implicated in cancer progression and shows promise as a vector in gene therapy studies

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